Reaction motor control system



May 17, 1949. L. LAwRENczE, JR., Erm.Y 2,470,564

REACTION MOTOR CONTROL SYSTEM 3 Sheets-Sheet l Filed Nov. 15, 1944 May 17, l'949 l.. LAWRENCE, JR., Erm. 2,470,564

REACTION MOTOR CONTROL SYSTEM y Filed` Nov. l5, 1944 5 Sheets-Sheet 2 INVENTORS ./AMES H Wma ATT RNEY on/ELL LAWRENCE JR.

May 17, 1949- l.. LAWRENCE, JR., ETAL 2,470,564

REACTION MOTOR CONTROL SYSTEM 3 sheets-sheet 3 Filed Nov. 15, 1944 /l y] E (M /45 'd' /M g 45 /14/ 4 f w EL X 77 f 'Ti E INVENToRs avc/l lawrence Jr: BY Jar/rw llf/ a ATTORNEY Patented May 17, 1949 REACTION Mo'roa coN'rRoL SYSTEM Lovell Lawrence, Jr., Pines Lake, Paterson, and `James H. Wyld, Pompton Lakes, N. J., assignors to Reaction Motors, Inc., Pompton Plains, N. J., a corporation of New Jersey Application November 15, 1944, Serial No. 568,596 7 Claims. (Cl. 60--35.6)

The present invention relates to apparatus for starting and controlling the operation of Jet reaction or rocket motors producing a useful propulsive thrust by the recoil action of a highvelocity gas jet, particularlyA reaction motors actuated by the continuous combustion in a chamber of two or more liquid propellants fed under pressure to the motor from tanks.

In operating a reaction motor of the liquid propellant type, several preliminary operations are performed before the motor can be started. and it is the principal object of the present invention to provide improved control devices for carrying out such preliminary operations.

The apparatus includes liquid propellant tanks connected to the motor through pressure operated valves and to the firing chamber of the motor through magnetically operated valves. A single switch is provided which, when closed. initiates a chain of events to ilrst connect the tanks to a source of nitrogen pressurey from which the liquid in the tanks is subjected to a predetermined pressure. When this pressure is attained. a pressure switch is operated to cause purging of the firing chamber and operation of the magnetically operated valves to introduce a combustible mixture into such chamber, which is ignited by a spark plug. The pressure in this chamber produced by the combustion therein operates a pressure switch, when the pressure reaches a predetermined value, and brings about the opening of the pressure valves in the main propellant conduits. whereby the motor is placed in operation with the propellants being ignited by the heat of combustion in the firing chamber. The resulting increased pressure in the motor operates a further pressure switch to cut off the supply of propellant to the ignition chamber, and the motor continues to operate uninterruptedly.

It is a further object of the invention to provide control devices in the system whereby, upon failure of either current or operating pressure, the

causes closure of one valve and opening of a second, so that for operation pressure is required for one valve and removal of pressure is required for the other.

Another object of the invention is to provide a device for effecting a water and hydrocarbon mixture to the motor through a pressure closed valve, and in which failure of the valve to close f will cause water to iiush the motor.

A still further object is to provide a reaction motor of improved construction wherein more efficient intermingling of propeilants is attained and more efdcient heat exchange is obtained.

Other objects of the 'invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode. which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a diagram showing the interconnecting conduits and circuit connections employed in the apparatus of the invention.

Fig. 2 is a sectional view of the improved reaction motor.

main propellant supply valves will automatically close and the motor will be automatically purged of any unburned fuel.

A more specific object of the invention is to provide an improved starting `control device for a reaction motor wherein an initial ilow of propellant iiuid is fed to the motor and ignited, and in which the pressure resulting in the motor from said initial ignition causes increased flow of propellant fluid to the motor.

A still further object of the invention is to provide a multiple valve control between the nuid tank and the motor in which control pressure operated valves in which-gas Fig. 3 is a diagrammatic showing of a normally open, pressure operated valve used in the system.

Fig. 4 is a diagrammatic showing of a normally closed, pressure operated valve.

Fig. 5 is a diagrammatic showing of a safety head.

Fig. 6 is a diagrammatic showing of a pilot valve used in the system.

The complete coordinated system is diagrammatically illustrated in Fig. 1 and includes reaction motor M, liquid oxygen, gasoline and water reservoirs designated TI, T2 and T3 respectively. Intermediate the reservoirs and motor is a pair of like valves separately designated Vl and'VI, and a further pair of like valves separately designated V3 and V4. Above each tank Tl, T2 and T3 there is provided a valve V5, Vt or V1, whose construction is similar to that of valve Vl and V2. A further regulator valve R2 is also provided to regulate the application of nitrogen gas pres.- sure from pressure spheres SI to the several valves. Valves Vl, V2, Vl, V6 and V1 are gas pressure. when applied, will close a normally open valve. A bulletin entitled General Controls," catalogue No. 51 (1941) published by the General Control Company of New York, illustrates a cross-sectional view of such valve on page 9 thereof. Figure 3 of the drawings shows a diagrammatic representation of one such valve for example, valve V1. Valves V3 and V4 (see Figure 4) are normally closed valves and a section of such a valve is shown on page of the catalogue referred to. Safety heads SH (see Figure 5) are of the well known type illustrated in a folder issued to the trade by Black, -Sivalls and Bryson, Inc. of Kansas City, Moi, entitled 9B. S. 8: B. Safety Head Pieces." Pilot regulator RI (see Figure 6) is of the well known type illustrated in a folder issued by the Grove Regulator Company of Oakland, Calif., entitled Grove Automatic Dome Loader. Valves SV3, SV5, SVB and SV1 are well known magnetic valves illustrated on page 36 of catalogue 51 referred to. Switches PSI, PS4, etc. are well known valve-operated switches of the type manufactured by Cook Electric Company of Chicago, Ill.

Interconnecting the several devices identified is holds the member |39 in the position shown.

When gas pressure is applied through conduit H2 to chamber |4| the diaphragm is flexed to force member |39 into valve closing position.-

Upon release ofthe pressure, spring |42 causes reopening of the valve.

A valve of the V3 type is represented in Fig. 4 wherein conduit 60, for example, enters into a chamber |43 which has connection through a port ,K |44 with an exit conduit 48. A valve member 45, urged by a spring |46, normally closes the port,

and this member has a rod connection |41' with the center of a diaphragm |48. When gas pressure is applied through conduit 11 to chamber |49, the diaphragm is flexed to lift rod |41 and valve member |45 to open the port. Upon release of the pressure, spring |46 causes reclosure of the valve.

Fig. 5 shows a well known form of safety head in which a conduit such as |50 connects with a chamber 5| closed by a diaphragm 52 with a predetermined bursting limit, so that if the pres-l sure in the chamber exceeds the limit, diaphragm |52 will burst and the pressure relieved to the atmosphere through opening |53.

Fig. 6 shows diagrammatically a well known form of pilot regulator RI which supplies pressure to a conduit such as |55 from a conduit such as |54 which latter is under a pressure greater than the maximum delivery pressure desired. In operation, the manually operatedvhandwheel |56, rotatable in housing |51, increases the tension of a Spring |58, against diaphragm |59, which through integral box and rod |6| forces ball |62 into valve opening position to effect a conrection from conduit |54, through port |63,

' of the structural arrangement chamber |64 to conduit |55. When this pressure,

acting on the under side of diaphragm |59, produces a force equal to the adjusted spring tension, the diaphragm rises, and ball |62 under the action of its spring |65, closes the port |63. Reduction of the spring tension, is accompanied by rising of box |60 away from a ball |66, normally closing a port |61, so that the pressure in chamber |64 is relieved through opening |68, port |61 and opening |69 to they atmosphere, thus .auto-- 4 matically bleeding enough gas to maintain the adjusted pressure at the set point.

A control panel I0 has switches mounted thereon by means of which electric circuits are controlled to initiate and control the operation of the apparatus as will be set forth hereinafter. Be-v fore doing so, a-brief description will be given of the motor showr in Figs. 1 and 2.

The reaction matan-The motor M shown ir Figs. 1 and 2 is of the self-cooled or regenerative type and consists of an inner combustion chamber 24, wherein combustion occurs, and an expansion nozzle 25 through which the burning gases are expelled, thereby producing a propulsive thrust. To prevent overheating of the combustion chamber 24 and nozzle 25 by the hot gases, an external cooling jacket and baiile 21 are provided. These are separated from chamber 24 and nozzle 25 by a narrow annular passage 28. One of the liquid propellants (gasoline and water) is fed to the annular space outside baille 21 and flows through passage 28, thereby cooling nozzle 25 and chamber 24. The propellant is thereby heated and escapes into the interior of chamber 24 through ports 29, mixing with the other propellant (liquid oxygen) which is injected through ports 30 from manifold 3|. Between baffle or filler block 21 and jacket 26 there is arranged a ring of spacer ns 21a which serve to break up the combustible entering through port |23. Along the length of passage 28 there are further rings of spacer ns 26a, inclined as shown, so that as the propellant travels through passage 28 it is broken up by fins 26a and given a spinner motion which serves to break up gas and liquid films and bubbles that may be present. Within oxygen ports 30 are located spiral springs 39a which serve to give a spin to the oxygen streams and make for better combustion and mixing of the propellants.

The spinner rings 26a and 21a, in addition to creating turbulence as the fuel passes through, serve to obtain an even distribution of the fuel over the outer surface of chamber 24. This is especially important since the intense heat within the chamber will cause burning vat spots or areas where no heat exchange takes place. The angle of inclination of the slots in rings 26a and 21a and the width thereof is such that no longitudinal stream may form and the fuel will be evenly guided.

lIn this type of reaction motor illustrated, the temperatures attained in the combustion chamber are in the neighborhood of 3500 centigrade, and it is therefore extremely important that the propellant flowing through passage 28 be moved at a rapid rate and also that it be so evenly distributed over the outer surface of chamber 24 as to prevent burning out of the chamber wall. In the prior art of reaction devices that were utilized to drive turbine blades or the like, temperatures were necessarily considerably lower 'to avoid -burning the turbiner blades and therefore heat exchange problems such as encountered herein, where the motor is the prime mover, were not encountered.

The provision of baffles 26a, 21a, or equivalent devices is necessary to obtain a uniform distribution of coolant, as without such devices the coollant would seek to iiow in a; restricted `stream developing air pockets of uncooled wall space, which at the high temperatures noted'would result in a hole being burned through the wall at that pocket. The spacing forming the passage 28 between wall 24, l25 and lbaille Tand jacket 26 is made quite narrow, as this will assist in the distribution of the coolant and in its more rapid flow.

The ignition bunten- The ignition burner comprises a firing chamber 32 suitably secured to the motor proper and is provided with an oxygen intake port 33 and a gasoline intake port 34,which ports are constructed to effect a readily combustible mixture which is ignited by the spark plug 35 and passes out through orifice 36 into the main combustion chamber 24, producing `an intense flame which ignites the combustible mixture in chamber 24. As will be explained in detail here inafter, a charge of combustible mixture is first fed to the firing chamber 32 and, when this has become ignited, the pressure within the chamber will cause operation of valves through which propeilants may thereafter be fed to the main combustion chamber 2d. The inner end of spark plug 35 is surrounded by a passage 31 having a port 38 through which a small stream of nitrogen gas is continuously directed around spark plug 35 to dry and cool the latter. This gas stream is kept small enough to avoid interference with the ignition of the fuel mixture in the firing chamber.

Valve system-The propellants are contained in the three pressure tanks T| (liquid oxygen), T2 (gasoline) and T3 (water). Safety heads SH containing diaphragms set to burst before excessive tank pressure develops are provided on these tanks. The tanks are filled through filling valves Ht. The usual tank pressure is 300 lb./sq. in. and is provided by feeding nitrogen gas into the tanks irom regulator valve R2, which in turn is fed from a set of three high-pressure spherical nitrogen tanks Si. The nitrogen spheres are charged through valve Hi from a battery of commercial nitrogen cylinders or a pump. A safety head SH with bursting diaphragm protects the spheres against excessive pressure. Shut-off valves H2, Hi i, HIE are provided to isolate regulator valve R2 from the tanks when repairing or adjusting it. The regulator R2 is controlled by gas pressure supplied through conducit 91 by a pilot regulator Ri, as explained later.

The propellants are fed to the reaction motor M through valves VI, V2, V3 and V4. The main valves Vi and V2 control the flow of liquid oxygen and of mixed gasoline and water respectively. They are mounted -close to the motor to provide a rapid fuel shut-off and are normally open when the control gas pressure is shut off To provide against failure to shut off the propellants in case of damage to valves VI or V2 or malfunction of them, a second set of emergency or safety valves are provided, oxygen valve V3 and gasoline valve Vl, which are normally closed when control gas pressure is shut off. These are mounted near the propellant tanks some distance from the motor, and are operated by a separate set of controls as described later. No safety valve is provided for the water, so that motor M is automatically flushed out with water if valve V2 fails to close.

Another set of diaphragm valves V5, V6 and V1 are connected'to the tops of the propellant tanks to vent off the gas pressure in these tanks after completing a run. These valves are normally open when control gas pressure is shut off. The oxygen tank vent V5 exhausts directly into the air at |25. The water tank vent V1 is connected to the oxygen valve VI by way of conduit |21, and the gasoline tank vent V6 is connected to the gasoline valve V2 by way of conduit |28. This ensures that any propellant remaining in the valves,

, 6 fuel lines. and motor after a run will be thoroughly purged out by the vented nitrogen gas.

At the beginning of a run, gasoline is supplied to the ignitor by way of conduit H8, which'includes a solenoid valve BV2 and metering orice |0| (which also includes a filter screen and check valve |32). Oxygen gas is supplied to the intake port 33 of the ignitor through the evaporator coil E (heated by the surrounding air) and the solenoid valve SVI.

The control pressure for controlling regulator valve R2 is provided by the pilot regulator valve Ri, which feeds nitrogen gas at 350 lla/sq. in. To ensure that nitrogen pressure will still be available to operate the controls in case of exhaustion of the pressure in tanks Sl, a small high-pressure sphere S4 is provided ahead of regulator RI, isolated from the main nitrogen spheres by a check valve |33. The nitrogen feed from pilot regulator Ri is turned on and off by the solenoid valve SV4. From SV4 the nitrogen` control pressure system branches oil in several directions. A three-way solenoid valve SVB leads to regulator R2. Valve SV3 is normally vented in the off position, but feeds nitrogen to regulator R2 when its solenoid is energized. This pressure is applied to the right side of the diaphragm R2a in regulator R2, thereby causing the valve R2b in R2 to open and feed nitrogen to the tanks TI, T2, TSuntil the tank pressure reaches 300 lb./sq. in., when regulator R2 will shut off. Diaphragm R2a has a connection with valve B2b, as shown so that valve R21) follows the movement of the center of diaphragm R2a. Thus pressure applied to the right side of R2a will cause valve R2b to shift to the left and uncover the end of conduit 98 to allow nitrogen to flow into the chamber of the valve and out through conduits 8| and B2. (The difference of 50 lb./sq. in. in outlet pressure of RI and R2 is owing to the force required to push the valve R217 in R2 open against the nitrogen pressure.) v

Control for working the main propellant valves VI and V2 is supplied through the three-way solenoid valve SV5 (a normally open" valve). When current is off, uid pressure is supplied to valves VI, V2 closing them. When the solenoid of valve SV5 is energized, the pressure is vented, causing valves Vl, V2 to open. The vent valves V5, V6, V1 are actuated by another three-way solenoid valve SV1 of the normally-closed type. When SV'I is off, the control pressure is vented from valves V5, V8, V1, causing them to open, while when the solenoid of valve SV1 is energized, V5, V6, V1 are closed. It will be noted that the safety valves V3 and V4 are connected to the same control pressure lines as the valves V5, VB, V1, sov that when the latter are open the safety valves are shut, and vice versa.

Another three-way solenoid valve SVG is provided for purging the spark plug 35 with nitrogen gas after each run. The valve SVB is connected to a small tank Tl. When valve V6 is oif," TI is connected to regulator RI by way ,of valve SV4, and charges upto 350 lb./sq. in. When the solenoid of valve SVG isenergized, tank T4 is disconnected from regulator RI and vented off through a check valve |33 horizontally to the right of valve SVB, and the interior of spark plug 35, thereby purging out any gasoline orwater lodged in the plug and ignitor, leaving them clean and dry. A small orifice |02 bypasses valve SV and causes a small stream of nitrogen gas to circulate continuously through plug 35 to dry and cool the latter. This gas stream is kept small enough to avoid interference with the ignition of the fuel mixture in the burner. l

Two pressure switches PS2 and PS3 (set to close at 125 lb. and 50 lb./sq. in. respectively) and a pressure gage G3 are attached to the purge line leading to plug 35 and the burner. The switches control the action of the various solenoid valves, as described later. The gage G3 indicates the pressure in the ignition burner. Since this pressure is the same as that in the main motor M when the latter ls firing, gage G3 also serves to indicate the main motor pressure, and thus the propulsive thrust, since the latter is nearly proportional to the combustion chamber pressure.

Another pressure switch PSI (set to close at 250 lb./sq. in.) is connected to tank TI through hand valve H6, while a fourth pressure switch PS4 (set to open at lb./sq. in.) is connected to tank T4.

For convenience in setting and adjusting the pressure switches, a set of hand shut-off valves H5, H6, H1 are provided. To set the pressure switches, regulator Rl. is set to zero pressure, valves H3, H4, H6 and HI3 are al1 closed, valves SV4, H5, H1 are opened, and pressure is fed to the purge line and the switches by slowly opening regulator R| manually. The pressures at which the various switches close (as indicated by a test light or voltmeter connected to them) are noted on pressure gage G2 connected to the output of regulator RI, and any necessary adjustments of the switches are thenmade. To lower the pressure, H1 is closed and HI3 slowly opened so that the pressure is relieved through the spark plug 35 and the combustion chamber. (See Fig. 2.)

To check main regulator R2, valves H4, H5,

H1, HII and HI2 are' closed and valves H3 and.

H2 left open. Regulator RI is then adjusted until the output pressure of regulator R2 as indicated by gage G4 reaches the proper amount. The corresponding pressure on gage G2 is then noted, and regulator RI is thereafter' always set to give this operating pressure. To release the pressure in R2, valve H3 is closed and H4 is opened, allowing the pressure to leak off through the vent in valve SV3.

In normal operation, valves H2, H4, H6, HI I, HI2 and H|3 are left open, while valves Hl, H3, H5, and H1 are closed, together with illling valves H8.

Operation-On the control panel I0. (Fig. 1) is a key switch SWI which, when closed (after safety switch SW2 has been closed), will supply current from battery B to wire |03 and to an indicator lamp |04. There is' also a three position switch represented by a pair of contact arms |05 shown in normal off position, which are movable concurrently to a start or horizontal v position and to an upper or .run position. These positions are designated l, 2 and 3 in the drawings.

When switch arms |05 are moved to their 2 or start position, the solenoids of valves SV3, SV4

and SV1 will become energized through a circuit traceable from battery B, switches SW2, SWI,

left hand arm |05, wire |08 and in parallel through the solenoids of the threeA valves to ground. Operation of valve SV4 permitsnitrogen to ilow from pilot regulator RI to conduits |01, |08 and |09 and operation of valve SV3 connects coduit |08 to conduit 91, so that regulator valve R2 will have pressure applied thereto to open said valve, whereupon pressure from the spheres SI is exerted through conduit 98, and conduits 8| and 82 to the tanks TI, T2 and T3.

When the tank pressure reaches 250 lb./sq. in., pressure switch PSI is operated through conduit I0 to close contacts PSIa which thereupon complete a circuit fro?, wire |03, contacts PSI a, and lamp II I to groun -to indicate that tank pressure is on. Operation oi' valve SV1 closes the vent therethrough and connects conduit |09 to conduit II2, so that pressure from pilot regulator RI is exerted through conduits |09 and II2 to valvesv V5, V6 and V1 to close them. This occurs while pressure is building -up in the tanks, so that the vent valves are closed when the operating pressure of 250 1b./sq. in.,ls reached. Pressure from conduit I|2 also branches through conduits 11 to valves V3 and V4 to open these valves. Opening of valve V3 connects valve VI with tank TI and opening of valve V4 connects valve V2,with tank T2 through conduit I3, and a. box or chamber ||3a into which water is also directed from tank T3 through conduit II4. Both the gasoline and water are fed under pressure (250 lb.) into chamber ||3a wherein they commingle and pass through conduit |23 to the motor when valve I2 opens. The valves VI and V2 are held closed at this time through nitrogen pressure from conduit |09, through normally connecting valve SVB and conduits |22 and 5I and will open as soon as this pressure is cut oi by operating valve SVI to vent conduit |22.

Pressure in conduit |09 is applied through normally connecting valve SVS to a small tank T4 and, as the pressure builds up in this tank, pressure switch PS4 operates to open its contacts PS4a. With the solenoid of valve SVS deenergized as at present, conduit |09 is connected only to tank T4 and is disconnected from a conduit I I 6. The positions of the valves at this time may be termed their start or normal positions, i. e., at the start position valves VI and V2 are closed.

Switch arms |05 are now moved to their 3 or run position Where a circuit is now completed from battery B, switches SW2, SWI, wire |03. left arm |05 and Wire I 06 to maintain the solenoids of valves SV3, SV4 and SV1 energized. A further circuit is traceable from battery B, switches SW2, SWI, wire |03,' contacts PSIa, right arm |05, wire II5, solenoid of valve SVS to ground. Operation of valve SVS disconnects tank T4 from conduit |09 (through which it has been charged) and connects it to conduit Iii and thence through the chamber 31 (Fig. 2) surrounding spark plug 35 to blow oil' and clear out any moisture or dirt in these parts. When vthe pressure in tank T4 has fallen to 15 lb./sq. in. or less (which occurs in a few seconds), the contacts PS4a of pressure switch PS4 reclose and through them a. circuit branches from wire II5, through contacts PS4a, wire II1, contacts Ya of a relay coil Y, wire I I8, which branches to solenoids of valves SVI and SV2 and thence to ground. A branch wire ||8 extends to primary winding o! a spark coil SC whose secondary Winding is connected to spark plug 35.

Operation of valve SV2 permits gasoline to ow through conduit I|9 to the ring chamber 32 yand operation of valve SVI permits oxygen to ilow from coil E to the chamber. Ignition thereupon takes place and a pressure of about 70 lb./sq. in. is developed in the ring chamber, which is transmitted through conduit |20 to switch PS3 to cause the related contacts PS3a to close. Closure of these contacts completes a circuit from wire II5, contacts PS4a, wire II1, contacts PS3a, and Wire |2I to solenoid of valve .SV5, closing this normally open valve to disconnect conduit III from conduit |22 and 5| and valves Vl and V2 to allow opening of these main propellant valves and permit a greater iiow to motor M, through conduits Il and |22.

As soon as the motor M develops a pressure of 125 lla/sq. in. or more (which occurs almost instantly), pressure switch PS2 is operated and closes its contacts PS2 to complete a circuit traceable from current line ||5. contacts PSla (reclosed), contacts PS2a, wire |24 to relay Y and ground. The relay opens its contacts Ya and closes itsl contacts Yb' and Yc. Opening of contacts Ya deenergizes the solenoids of valves SVI and SV2, shutting of! fuel supply to the ignitor and current to the spark coil SC. Closure of contacts Ye sets up a holding circuit for the relay traceable from current wire |05, contacts Yc, and relay Y to ground, which will now maintain the relay energized until switch arms are moved out of the 3 positions. The relay contacts Yb are wired in parallel with contacts PSla and with the former now held closed the circuit through solenoids of valves SV5 is maintained energized to keep valves VI and V2 open.

Motor M is now receiving a constant flow of oxygen througlV conduit 50, and a constant flow of a mixture of gasoline and water through conduit |23, and this will continue until the supply is exhausted or until switch arms |05 are shifted from their run positions.

If arms |05 are shifted to their 2 or start positions, the solenoids of valves SVS, SVI and SV1 will be deenergized and immediately reenergized to keep pressure in tanksTl, T2 and T3. Switch PSI will keep its contacts PSIa closed and lamp will remain illuminated. With current interrupted to wire H5, solenoid of valve SVB will become deenergized and pressure will build up alain in tank T4, operating valve PS4 to open contacts PSIa and deenergize the solenoid of valve SVi'r. This results in connecting conduit |22 to pressure conduit |09, so that valves Vl and V2 are operated to cut off the fuel supply. Relay Y also becomes deenergized upon opening of its holding circuit, throughA the left switch arm |05. The apparatus is now in the condition as described, Just prior to moving the switch from its start to run position.

To resume operation, the arms |05 are shifted back to run position and the sequence of events described will l"ne repeated, beginning with tank T4 first blowing off to clear the ignition chamber.

|05 is moved from its run to start positions, all circuits are momentarily broken, including the circuit to the solenoid SV1 which thus causes momentary venting of conduit ||2, so that valves V5, V6 and V1 open allowing pressure in tank T2 to vent through conduit |28 and tank T3 to vent through conduit |21 and 52 to thus purge the motor M of any unburned fuel before the circuit to solenoid SV1 is reestablished and insures that upon return to run position the motor will be free of combustible charge.

With arms |05 moved to off" position (or by opening either switch SWI or SW2), current is interrupted to all the solenoid valves. Valve SV1 is vented to atmosphere so that valves V5, V6 and V1 are vented through conduit II2, allowing these valves to open under pressure of the nitrogen in the tanks. Pressure in ytank TI will be vented through conduit |25 to atmosphere. Pressure in tank T2 will be vented through conduit |26, through valve V2, conduit |23 and Itis to be particularly noted that, when switch trogen control pressure will also stop since if there is no pressure in conduit ation will follow as explained.

l0 motor M, and in .ank'ltwillbevented through conduits |21, 52, valve VI, conduitll and motor M. thus purging the motor of any unburned fuel.

It is to be noted that any current failure will shut of! the motor in the same manner as though the switch were thrown to its of!" position, and it is to be further noted that failure of the nithe motor, H2, valves V2 and Vl close to cut oiI the' supply of propellants to valves VI and V2. Any stoppage of the motor will also cause venting of the tanks T2 and T3 through the motor, so that the latter is purged and returned to a safe oil condition. l

In the foregoing lt was stated that the switch is moved from its oil to its start and then to its run" position. It may also be moved directly from of' to runf in which case the' same sequence of events occurs, namely, valves SVS, SV4, and SV1 operate concurrently and the tanks TI, T2, T3 become charged. ATank pressure will operate switch PSI and the oper- The switch PSI, through its contacts PSIa prevents any'operation unless sufilcient pressure is first built up in tank T While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a single modificav, tion, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention therefore to be limited only as indicated by the scope of the iollowing claims.

What is claimed is:

1. In a starting system for a reaction motor, a combustion chamber having an ignition device, in combination with a reservoir containing a liquid fuel, a conduit between said chamber and reservoir, a normally closed valve in said conduit, a source of gas pressure, means for connecting said reservoir to said pressure source to create pressure in the reservoir, means responsive to the pressure in said reservoir when it reaches a predetermined value for causing gas from said pressure source to purge said ignition device, and means effective upon completion of said purging for automatically opening said valve and for operating the ignition device, whereby fuel under pressure is fed to the chamber and ignited.

2. In a starting system for a reaction motor, a combustion chamber, a reservoir containing a liquid fuel, a conduit between said chamber and reservoir, a normally closed valve in said conduit, a pressure source, means for connecting said reservoir to said pressure source to create pressure in said reservoir, means responsive to the pressure in said reservoir when it reaches a predetermined value for causing opening of the valve in said conduit, whereby fuel under a predetermined pressure will pass to the chamber and further means responsive to the pressure in the chamber when it reaches a higher predetermined value for effecting reclosure of the valve.

3. In a starting system for a reaction motor, a combustion chamber having an ignition device, in combination with a reservoir containing a liquid fuel, a conduit between said chamber and reservoir, a normally closed valve in said conduit, a source of gas pressure, means for connecting said reservoir to said. pressure source to create pressure in the reservoir, an auxiliary tank containing a charge of gas under pressure, means responsive to the pressure in said reservoir, when it reaches a predetermined value for causing the charge of gas in said tank to exhaust through said '.gnition device to purge the same, and means responsive to the exhaustion of said charge for causing opening of said valve and for operating said ignition device, whereby fuel under pressure is fed to the chamber and ignited.

4. 'I'he invention set forth in claim 3 in which the valve is electrically operated, and the means responsive to the exhaustion -of the charge in said auxiliary tank comprises a pressure switch connected to the tank and an electric circuit is provided and closed by said switch when the pressure in the tank drops to a predetermined value, to operate said valve.

5. In a starting system for a reaction motor, a combustion chamber having an ignition device, in combination with a reservoir containing a liquid fuel, a conduit between said chamber and reservoir, a normally closed valve in said conduit, a source of gas pressure, means for connecting said reservoir to said pressure source to create pressure in the reservoir, an auxiliary tank normally connected to said pressure source to thereby receive a charge of gas, means responsive to the pressure in said reservoir when it reaches a predetermined value for disconnecting the tank from said source and for causing the charge of gas in said tank to exhaust through said ignition device to purge the same, and means responsive to the exhaustion of said charge for causing opening of said valve and for operating said ignition device, whereby fuel under pressure is fed to the chamber and ignited.

6. In a system of the class described, a combustion chamber, a reservoir containing a liquid fuel, a main conduit and an auxiliary conduit between said reservoir and said combustion chamber, means for causing fuel to ow from the reservoir to the chamber through the auxiliary conduit, an ignition device in said combustion chamber operative to ignite the fuel fed thereto, means responsive to the pressure created in said chamber means controlled thereby when said pressure reaches a predetermined value for causing fuel to flow from the reservoir to the chamber through the main conduit and further pressure responsive means eil'ective when the pressure in the chamber reaches a higher predetermined value for shutting oil' the flow of fuel through the auxiliary conduit.

7. In a system of the class described, a combustion chamber, a reservoir containing a fuel, a main conduit and an auxiliary conduit between said reservoir and said combustion chamber. means for causing fuel to flow from the reservoir to the chamber through the auxiliary conduit, an ignition device in said combustion chamber operative to ignite the fuel fed thereto, means responsive to the pressure created in said chamber, means controlled thereby when said pressure reaches a predetermined value for causing fuel to ilow from the reservoir to the chamber through the main conduit and further pressure responsive means effective when `the pressure in the chamber reaches a higher predetermined value for rendering the ignition device ineffective.

LOVELL LAWRENCE, Ja. JAMES H. WYLD.

REFERENCES The following references are of record in the file of this patent:

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